Method of impregnating a metallic mass or metal article with other metal



impregnate into the surface of the base.

Patented May 3, 1938 PATENT OFFICE METHOD OF IMPREGNATING A METALLIC MASS OR METAL ARTICLE WITH METAL Frank Leveriek, Blaby,

assignor to Follsain don, England OTHER near Leicester, England, Syndicate Limited, Lon- No Drawing Application February 18, 1936, Se-

rial No. 64,583. In Great Britain February 20,

2 Claims.

The process of impregnation is the art ofiforming at and in the surface of a metallic mass or article a layer of alloy of the metal of the metallic mass or article with another metal.

My invention refers to that particular process of impregnation in which the metallic mass or article containing metal of the ferrous series (which I call a base) is heated with some substance which contains the metal it is desired to I call the metal referred to an ingoing material.

The invention consists in mixing a metallic salt and glycerine with the ingoing material before heating and then heating the base in the presence of such mixture to a temperature at which an alloy of the base and ingoing material will be formed.

Although I do not wish to be restricted to them, I have successfully'used as the metallic salt, the

following:calcium nitrate, potassium nitrate,

lead acetate, calcium nitrite, calcium carbonate, sodium thiosulphite. Glycerine is in all cases used in the mixture containing any of the above metallic salts.

I carry out the process of impregnation by any usual means, for instance by surrounding the base with an active mixture, by which is meant the impregnating medium and added operator enclosing the whole in a box, and raising the tem- 0 peratures suitably. If some of the parts of the active mixture are liquid or gaseous, then detail alterations such as the provision of suitable inlet tubes may be necessary.

Although I do not wish to be bound to any 35 specific cases, the following practical example of my preferred conditions, but a compound formed by the action of moderate heat on copper together with-calcium nitrate and glycerin will dissociate as required. Therefore the active mixture is made of copper, as metal (the impregnating medium) to which is added 4 to 8 per cent. by weight of calcium nitrate (the operator) and 3 to 5 per cent. by Weight of glycerin (the activator).

The base is put into a box, surrounded by the active mixture, the box is closed, put into a furnace and the temperature raised. The rate of rise of temperature should not exceed 100 degrees centigrade per hour. When the box has reached a temperature of approximately 900 degrees centigrade the action will have started, and will be complete by the time a temperature of approximately 1000 degrees centigrade has been reached. I prefer to stop the temperature rise, and keep the box at 960 to 1000 degrees centigrade for three to four hours after which period the base will be found to be impregnated to a depth of about one to two millimeters. The box is then cooled by withdrawing from the furnace, unpacked and the work is then finished.

I claim:--

1. A process for impregnating an iron base with another metal consisting in mixing a metal salt and glycerine with said other metal before heating and then heating the base in the presence of such mixture to a temperature within the range of 900 to 1000 C.

2. A process for impregnating copper into a mass or article containing iron which consists in mixing calcium nitrate and glycerine with the copper before heating and then heating the mass or article in the presence of such mixture to a temperature within the range of 900 C. to 1000 C.

FRANK LEVERICK. 

